Lightning arrester



Feb. 12, 1924. F. A. LIND LIGHTNING ARRESTER Filed May 6, 1919 iNVENTOR fFaa ar/c/r A L maf' WITNESSES:

ATTORNEY Patented Feb. 12, 1924.

FREDERICK LIND, OF TURTLE GREEK,

PENNSYLVANIA, ASSIGNDR T0 RVE$TING- HOUSE ELECTRIC & MANUFACTURING COMPANY, A GOBPORATIQN OF YENNSYL- VANIA.

LIGHTNING ARBESTER.

Application filed May 8,

. To all whom it may concern:

Be it known that I, FREDERICK A. Line, a citizen of the United States, and a resident of Turtle Creek, in the county of Allegheny and State of Pennsylvania, have invented. a new and useful Improvement in Lightning Arresters, of which the following is a specification.

My invention relates to lightning arresters and it has particular relation to arresters of the type usually known as multipath arresters and comprising two electrodes spaced apart by means of a discharge block composed of particles of conducting and norrconducting materials.

The object of my invention is to provide an arrcster of the character designated wherein any discharge of current through the block caused by voltage slightly above normal in the circuit to which it is attached will be allowed to pass to ground witl'iout, in any way, a fleeting the arrestcr and wherein any excessive discharge of current caused by a very high potential being inipressed on the circuit will automatically increase the resistance tl'iercoi to a point which will render a continuous flow of current through the established path. impossible and thereby cause the current to seek a new path, provided the voltage is still above normal.

Herctol'orc, it has been suggested to use a discharge hlock composed of a mixture of load peroxid and some insulating or some conducting granules which serve to either de crease or increase the resistance of the discharge block, this hlocl: being separated from the spaced electrodes by means of insulating films thereon. (he ohjcctiou to this type of arrester is that, u'hcna. potential sur e occurs on the line, whether 0? rclat' ly great or relatively small value, the in: ulzrting films will lie punctured aiuh due to the low re. stance of the load peroxid. an einrcssivo current will flow to ground, heating the lead peroxid and permanently changing its resistance to a much greater value so that even zr very slight increase in potential on the line will render a portion of the discharge liloclt pcri'mnenlly useless as a prolcclion against surges oi the voltage for which it was desiguei'l.

By my invention, I provide an arrestcr in which the discharge block cmnposcd of lead pe oxid and either condiul'ing or insulating material replaced by, a similar block 1919. Serial No. 295,b69.

formed of a mixture of particles of conduct ing, insulating and lead peroxid particles. Such a block. niayeoniprise particles of carborundurn and of lead peroxid separated by any sutiab'le insulating compound. The in sulating particles serve to hold the conducting and lead peroxid particles in invariable but spaced relation with respect to each other, therehy eliininatii'ig the necessity of the insulating film and improving the protection aiiiorded by the arrester. 1n the single figure of the accompanying drawing which re a sectional view of my an roster, show two conducting plates 1 and. which' lire connected to a supply line 3 and. to ground. 4, respectivelyuand are spaced aparthy means of a. discharge block 5 com-- posedofintermingled particles of conduct-- iug and non-conducting material and lead peroxid. The uoirconducting znz'zterial serves as a binder and also serves to insulate the mmducting and lead peroxid particles.

In. an 'arrester of this type, any small discharge of current of short duration will pass through the liloclr to ground without produclug any appreciable increase in the tci'npera ture thereof on account of the cooling eilect of the discharge hlock. l-lowever. should a small continuous current or a large current of any duration pass through the clock, it will be heated tl'iereliy and the lead peroxid inthe particular path followed by the can rent will he changed to a lower oxid of atively great resistance, thus either cholii 2.1;; of? the current or if it is of siu'licien'ly high potential, causing it to seek anothorpath of discharge. This same client will tend to seal any imperfection in the discharge hlocli due to aliuen ent of conducting particles and will thereby restore it to its originally intended. dischargevoltage breakdown.

One oi. the inherent properties of a discharge block composed of spaced. particles of cmiducting material is that conductance thcrcoi is substantially nil at the potential of the circuit which it is designed to protect and that any increase in potential thereof re sults in a decrease of resistai'ice at an even greater rate than the potential rises. This property causes relatively insignifimnt current to pass through the hlv'iclr at normal voltage of the circuit and causes a very large current to pass thcretlu'ough when excessive potentials are impressed thereon. On the other hand, the property of the lead peroxid,

till

thereof and in inverse relation to the current passing through said arrcster.

12. A. lightning arrester com rising two conducting electrodes one of wlich is con nected to a supply circuit and the other of which is connected to ground, and a dis charge block disposed intermediate said electrodes and embodyinga mixture of two materials, the conductance of one of which varies in direct relation with the potential of said circuit and the conductance of the other of which varies in inverse relation with the current passing through said arrester. v

13. A lightning arrester comprising two conducting electrodes one of which is connected to a supply circuit and the other of which is connected to ground and a dis charge block disposed intermediate said electrodes and embodying a. mixture of two materials, the conductance of one of which is substantially nil when normal potential is impressed on said circuit and which varies in direct relation with the potential of said circuits, and the resistivity of the other of said materials being substantially nil when relatively small currents pass through said discharge block and 'Which varies in direct relation with current passing therethrough.

ll. An electrical-tliscln1rge device co1nprising a plurality of spaced conductin members, means disposed intermediate said members the impedance of which varies inversely with the difference of potential be tween said members, and additional means disposed throughout the major portion of the space between said members, the re *sistivily of Which varies with the tempcrature thereof.

15. An electricahdischarge device com prising a plurality of spaced conducting members, means disposed intermediate said members the impedance of which becomes iaterially reduced when the potential dif terence between conducting members ex coeds a critical value, and additional means combined with said first named means whereby the resistivity of said block is caused to vary With temperature thereof.

16. An electrical-discharge device comrising a plurality of conducting members aving a space therebetweemineans disposed intermediate said members the impedance of which becomes materially reduced when the potential difference between conducting members exceeds a critical value, and addi- 'tional means disposed throughout the major said conducting members and adapted to seal any current path through said space upon the continuous passage of current therethrough. y

In testimony whereof, I have hereunto subscribed my name this 23rd day of April FREDERICK A. L ND, 

